Umbrella base



FIG. 1 is a front and top perspective view of an umbrella base, showing my new design;

FIG. 2 is a rear and bottom perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a right side elevation view thereof;

FIG. 7 is a top plan view thereof;

FIG. 8 is a bottom plan view thereof;

FIG. 9 is an enlarged view of a portion labeled, ‘FIG. 9 ’ in FIG. 1 ;

FIG. 10 is an enlarged view of a portion labeled, ‘FIG. 10 ’ in FIG. 3 ; and,

FIG. 11 is another perspective view thereof, shown in a using position.

The broken lines in the figures illustrate portions of the umbrella base that form no part of the claimed design. The dash dot dash lines in FIGS. 1, 3, 9 and 10 are for the purpose of depicting the boundary lines of the enlarged views and form no part of the claimed design. The broken lines of an umbrella in FIG. 11 shown in the drawings depict environmental structure that form no part of the claimed design. 

CLAIM The ornamental design for an umbrella base, as shown and described. 